Internal split field generator

ABSTRACT

A generator includes a coil of conductive material. A stationary magnetic field source applies a stationary magnetic field to the coil. An internal magnetic field source is disposed within a cavity of the coil to apply a moving magnetic field to the coil. The stationary magnetic field interacts with the moving magnetic field to generate an electrical energy in the coil.

RELATED APPLICATION

This application is related to U.S. patent application Ser. No. ______(Attorney Docket No. 13489/104), filed Jun. 4, 2009 and titled “ExternalSplit Field Generator,” which is incorporated by reference.

GOVERNMENT INTEREST

This application was made with United States government support underContract No. DE-AC05-00OR22725 awarded by the United States Departmentof Energy. The United States Government has certain rights in theseinventions.

BACKGROUND

1. Technical Field

This application relates to devices that convert mechanical energy intoelectrical energy and, more particularly, to generating electricalenergy through magnetic field interactions.

4. Related Art

A generator converts mechanical energy into electrical energy. Mostgenerators include an armature and a magnetic field source. Electricalenergy may be induced in a conductive member of the armature when thereis a relative movement between the armature and a magnetic field. Insome implementations, electrical energy may be generated at the armatureby passing a moving magnetic field across a stationary armature. Inthese configurations, the armature would be the stator of the generatorand the magnetic field source would be the rotor of the generator. Inother implementations, the electrical energy may be generated at thearmature by moving the armature through a stationary magnetic field. Inthese configurations, the magnetic field source would be the stator ofthe generator and the armature would be the rotor of the generator. Whenmechanical energy (e.g., a rotation force) is applied to the rotor ofthe generator, an electrical energy (e.g., current and voltage) may beinduced in the armature. The induced electrical energy may then beoutput to power other electrical devices.

SUMMARY

A generator includes a coil of conductive material. A stationarymagnetic field source applies a stationary magnetic field to the coil.An internal magnetic field source is disposed within a cavity of thecoil to apply a moving magnetic field to the coil. The stationarymagnetic field interacts with the moving magnetic field to generate anelectrical energy in the coil.

Other systems, methods, features and advantages will be, or will become,apparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the invention, and be protectedby the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a generator.

FIG. 2 is a cross-sectional view of the generator of FIG. 1.

FIG. 3 shows a first result of a magnetic field source rotating near anarmature of a generator.

FIG. 4 shows a second result of a magnetic field source rotating near anarmature of a generator.

FIG. 5 shows a third result of a magnetic field source rotating near anarmature of a generator.

FIG. 6 shows a fourth result of a magnetic field source rotating near anarmature of a generator.

FIG. 7 shows a fifth result of a magnetic field source rotating near anarmature of a generator.

FIG. 8 shows a sixth result of a magnetic field source rotating near anarmature of a generator.

FIG. 9 is an output waveform of electrical energy induced in an armatureof a generator in response to a half rotation of a magnetic fieldsource.

FIG. 10 is an output waveform of electrical energy induced in anarmature of a generator in response to a full rotation of a magneticfield source.

FIG. 11 shows a first generator with multiple armatures and multiplemoving magnetic field sources.

FIG. 12 shows a second generator with multiple armatures and multiplemoving magnetic field sources.

FIG. 13 shows one configuration for stationary magnetic field sources ofa generator.

FIG. 14 shows a second configuration for stationary magnetic fieldsources of a generator.

FIG. 15 shows a third configuration for stationary magnetic fieldsources of a generator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A generator may include an armature, a moving magnetic field source, anda stationary magnetic field source. Electrical energy may be induced ina conductive coil of the armature in response to an interaction betweenthe armature, the moving magnetic field, and the stationary magneticfield. The moving magnetic field source may be positioned adjacent to asubstantially neutral point of the conductive coil where the amount offlux from the moving magnetic field source would be balanced across bothsides of the coil about equally. In this position, the moving magneticfield source alone may not induce much, if any, electrical energy in thecoil. That result, however, may be substantially different when thestationary magnetic field is applied to the coil. The stationarymagnetic field may be generated to pull magnetic flux from the movingmagnetic field source back and forth across the coil as the polarity ofthe moving magnetic field alternates between north and south. When themoving magnetic field source is showing the coil a north polarity, moreof the flux will be located in one side of the coil. When the movingmagnetic field source is showing the coil a south polarity, more of theflux will be located in the other side of the coil. This fluxinteraction between the coil, the moving magnetic field, and thestationary magnetic field may result in an increased efficiency of thegenerator.

FIG. 1 is a generator 102 that uses moving and stationary magneticfields to generate electrical energy. The generator 102 includes aninternal magnetic field source 104 and an armature 106. The internalmagnetic field source 104 may generate a moving magnetic field thatinteracts with a stationary magnetic field to induce an electricalenergy in the armature 106.

The internal magnetic field source 104 includes a magnet 108 and a shaft110. The magnet 108 produces a moving magnetic field in the vicinity ofthe armature 106. In one implementation, the magnet 108 may be apermanent magnet with multiple poles. As the magnet 108 is rotated aboutthe axis of the shaft 110, a conductive member of the armature 106 mayexperience an alternating polarity from the internal magnetic fieldsource 104. The portion of the magnet 108 nearest to the conductivemember of the armature 106 may alternate between being a north pole anda south pole. In one implementation, the magnet 108 may have one northpole and one south pole. Therefore, the armature 106 may experience twopole changes per full rotation of the shaft 110 (e.g., from north tosouth, and then from south back to north). Alternatively, the magnet 108may have more than one north pole and more than one south pole.Therefore, the armature 106 may experience more than two pole changesper full rotation of the shaft 110. If the magnet 108 has two northpoles alternating with two south poles, then the armature 106 mayexperience four pole changes per full rotation of the shaft 110. Otherimplementations of the magnet 108 may include any other number of polesto provide different numbers of pole changes per rotation of the shaft110. In one such implementation, the magnet 108 may be a combination ofmultiple magnets that are arranged so that the same polarity is facingout all the way around the magnet 108. In this implementation, the polechanges experienced at the armature 106 may result from transitionsbetween one pole, such as a north pole, to a magnetically neutral areaof the magnet 108. Another transition would then occur when themagnetically neutral area transitions back to another north pole as themagnet 108 rotates.

In another implementation, the magnet 108 may comprise a field sourcecoil. To generate a moving magnetic field, an alternating current may beapplied to the field source coil. In this implementation, thealternating current excited coil generates a moving magnetic fieldwithout moving any mechanical parts. When the alternating current isflowing in one direction through the field source coil, the magnet 108will have a first polarity. When the alternating current is flowing inthe other direction through the field source coil, the magnet 108 willhave the opposite polarity. In this configuration, the generator 102 mayoperate as a transformer.

The armature 106 includes a frame 112, a coil 114, a first stationarymagnetic field source 116, and a second stationary magnetic field source118. The coil 114 may be formed from a conducting material, such as acopper wire. The coil 114 may be disposed about the frame 112. In oneimplementation, the coil 114 may include one or more conductive windingswrapped around the frame 112.

The frame 112 may include a core 120, one or more cavities 122, and anouter surface 124. The coil 114 may be wound on the outer surface 124 ofthe frame 112 so that the coil 114 is wrapped about the core 120. Theportion of the frame 112 that supports the coil 114 may be made of anon-conducting and non-magnetizing material, such as wood, plastic, orthe like. The core 120 may be made from a magnetizing material, such asiron, steel, ferrous alloys, or the like.

The cavity 122 of the frame 112 provides a space for the internalmagnetic field source 104 to generate a moving magnetic field near thecoil 114. The internal magnetic field source 104 may be rotated about anaxis inside the cavity 122. The axis may be the axis of the rotatingshaft 110. The frame 112 may include a passageway that allows therotating shaft 110 to reach the internal magnetic field source 104 inthe cavity 122. The cavity 122 may be filled with a magnetizing materialthat at least partially surrounds the internal magnetic field source104. The filler material may be placed around the internal magneticfield source 104 in a way that allows rotation of the internal magneticfield source 104.

The stationary magnetic field sources 116 and 118 may be substantiallystationary relative to the coil 114. In one implementation, thestationary magnetic field sources 116 and 118 may be connected with thearmature 106. Alternatively, the stationary magnetic field sources 116and 118 may be an integral portion of the armature 106. The stationarymagnetic field source 116 may be disposed on a first end portion of theframe 112 or core 120. In one implementation, the first end portion maybe the outermost end of the frame 112 or core 120. In anotherimplementation, the first end portion may be any portion of the frame112 or core 120 located on that side of the coil 114. The stationarymagnetic field source 116 may be located at a point to the left of thecoil 114 (based on the perspective of FIG. 1). The stationary magneticfield source 118 may be disposed on a second end portion of the frame112 or core 120. In one implementation, the second end portion may bethe outermost portion of the frame 112 or core 120. In anotherimplementation, the second end portion may be any portion of the frame112 or core 120 located on that side of the coil 114. The stationarymagnetic field source 118 may be located at a point to the right of thecoil 114 (based on the perspective of FIG. 1).

The stationary magnetic field sources 116 and 118 may comprise permanentmagnets or direct current energized elements, such as coils. Thepolarity of the stationary magnetic field source 116 is opposite thepolarity of the stationary magnetic field source 118. The stationarymagnetic field sources 116 and 118 are positioned to be attracted toeach other. In FIG. 1, the south pole of the stationary magnetic fieldsource 116 is closer to the coil 114 than the north pole of thestationary magnetic field source 116. The north pole of the stationarymagnetic field source 118 is closer to the coil 114 than the south poleof the stationary magnetic field source 118. In this configuration,there is an attraction between the south pole of the stationary magneticfield source 116 and the north pole of the stationary magnetic fieldsource 118. In other implementations, the north pole of the stationarymagnetic field source 116 and the south pole of the stationary magneticfield source 118 may be facing the coil 114 to provide the attractionbetween the stationary magnetic field sources 116 and 118.

The stationary magnetic field sources 116 and 118 apply a stationarymagnetic field to the coil 114. In one implementation, the stationarymagnetic field sources 116 and 118 may apply a stationary magnetic fieldalong a substantially longitudinal axis of the coil 114. When thestationary magnetic field sources 116 and 118 are disposed on the frame112 that supports the coil 114, the magnetic field between thestationary magnetic field sources 116 and 118 passes along or throughthe core 120 of the frame 112. When the coil 114 is wound on the frame112 about the core 120, the core 120 may define the longitudinal axis ofthe coil 114. Therefore, the stationary magnetic field may pass alongthe longitudinal axis of the coil 114 by passing along or through thecore 120.

The magnetic strength and position of the stationary magnetic fieldsources 116 and 118 may be based on a desired electrical output of thearmature 106. For example, the electrical output from the armature 106may depend on the strength and position of the stationary magnetic fieldsources 116 and 118. The strength and position of the stationarymagnetic field sources 116 and 118 may be set so that the stationarymagnetic field is strong enough to sufficiently pull the magnetic fluxfrom the internal magnetic field source 104 back and forth across thecoil 114. If the stationary magnetic field sources 116 and 118 are faraway or are weak, the stationary magnetic field may not be strong enoughto sufficiently pull the magnetic flux from the internal magnetic fieldsource 104 back and forth across the coil to induce electrical energy inthe coil as the internal magnetic field source 104 alternates polarity.Alternatively, if the stationary magnetic field sources 116 and 118 aretoo strong or too close together, then the stationary magnetic field mayinterfere with the ability of the moving magnetic field from theinternal magnetic field source 104 to interact as strongly with the coil114. The optimal position and strength of the stationary magnetic fieldsources 116 and 118 may be based on the material used to form the core120, the size of the coil 114, and/or the position of the internalmagnetic field source 104 relative to the coil 114. The strength andposition of the stationary magnetic field sources 116 and 118 may beadjusted until a desired output is achieved on the armature 106 based onthe other selected components and attributes of the generator 102.

In one implementation of the generator 102, the stationary magneticsources 116 and 118 may be N-42 Neodymium, ⅞ of an inch in diameter, ⅛of an inch thick, and with a surface field of about 2885 Gauss (0.2885Tesla). Alternatively, the surface field may be about 1000 Gauss toabout 5000 Gauss, although the range may depend on the magnetic fieldspacing and the core material. The strength of the external magneticfield source 104 may be about 2500 Gauss (0.25 Tesla). The distance ofthe external magnetic field source 104 may be about 1 mm from the coil114. Alternatively, the external magnetic field source 104 may bepositioned to be closer or further away from the coil 114, such as up toseveral inches away from the coil 114. Any of these sizes, numbers, ormeasurements may be adjusted based on the intended application.

The internal magnetic field source 104 may be positioned adjacent to asubstantially neutral point 126 of the coil 114. Depending on the shapeof the coil 114, the internal magnetic field source 104 may bepositioned substantially perpendicular to the substantially neutralpoint 126 of the coil 114. The substantially neutral point 126 may bethe point in the coil 114 where the amount of flux from the internalmagnetic field source 104 is balanced across both sides of the coil 114about equally (without the interaction with the stationary magneticfield). If the internal magnetic field source 104 is located adjacent tothe neutral point 126 of the coil 114, then the flux change from theinternal magnetic field source 104 may produce a minimal inducedelectromagnetic force in the coil before addition of the stationarymagnetic field from the stationary magnetic field sources 116 and 118.In this position, due to the balance across the coil, the movingmagnetic field alone may not induce much, if any, electrical output fromthe coil 114. That result, however, may be substantially different whenthe stationary magnetic field is applied to the coil 114.

To identify the substantially neutral point 126 of the coil 114, theinternal magnetic field source 104 may be placed adjacent to a firstpoint on the inner side of the coil 114. The internal magnetic fieldsource 104 may then be rotated to generate a moving magnetic field inthe vicinity of the coil 114 before the stationary magnetic field isapplied to the coil 114 (e.g., before stationary magnetic field sources116 and 118 are placed on the armature 106 or other location). As theinternal magnetic field source 104 rotates in the first chosen location,the output voltage from the armature 106 may be monitored. If thearmature 106 is outputting little or no voltage as the internal magneticfield source 104 rotates at the first chosen location, then thatlocation may be near the substantially neutral point 126 of the coil114. If the armature 106 is transmitting a relatively large amount ofvoltage as the internal magnetic field source 104 rotates at the firstchosen location, then that location may not be near the substantiallyneutral point 126 of the coil 114. In that situation, the internalmagnetic field source 104 may be moved adjacent to a second point on theinside of the coil 114. The output voltage is measured with the internalmagnetic field source 104 rotating at this new location. Once a positionis determined for the internal magnetic field source 104 that results inlittle or no output voltage from the armature 106 (before the stationarymagnetic field is applied to the coil 114), then that position may beidentified as the substantially neutral point 126 of the coil 114.

When the internal magnetic field source 104 rotates at the neutral point126 of the coil 114, no output voltage may result at the armature(before the stationary magnetic field is applied to the coil 114). Inpractice, however, some small amount of voltage may be transmitted fromthe armature 106 even if the neutral point 126 of the coil 114 isproperly identified. Therefore, the neutral point 126 may include theabsolute neutral point of the coil 114 as well as surrounding areas thatmay result in some small amount of voltage. The acceptable level ofvoltage induced when the internal magnetic field source 104 is at theneutral point 126 varies based on user defined tolerances as well as thedesired strength of the output voltage. In one implementation, theneutral point may encompass several different possible positions for theinternal magnetic field source 104 within an area around the absoluteneutral point so that the output voltage, when the stationary magneticsources 116 and 118 are not in place, would be about 5% of the outputvoltage that would occur when the stationary magnetic sources 116 and118 are in place. In other implementations, other output voltagetolerance levels may be used, such as 20%, 10%, 1%, 0.1%, or the like.

In one implementation where the expected output voltage is about 4 voltswhen the stationary magnetic sources are in place, the output voltagewhen the stationary magnetic sources are removed may be in the range ofabout 5 mV (e.g., about 0.1% of the 4 volt expected output). However,the output voltage when the stationary magnetic sources are removed maybe higher or lower than 5 mV, depending on the size and uniformity ofthe coil 114, and the acceptable positioning of the external magneticfield source 104 around the neutral point 126.

When the coil 114 is substantially uniform and symmetric (e.g., theindividual windings of the coil 114 are uniformly distributed along thelength of the coil 114), the substantially neutral point 126 of the coil114 may comprise the center point of the coil along the length of thecoil, as shown in FIG. 1. Therefore, the internal magnetic field source104 may be placed substantially perpendicular to the center point of thecoil 114. If the coil 114 is not substantially uniform or symmetric,then the substantially neutral point 126 may be offset from the centerof the coil 114 (e.g., to the left or right).

FIG. 2 is a cross-sectional view of the generator 102 of FIG. 1 (e.g., across-sectional slice at the center line of FIG. 1). Multiple instancesof the internal magnetic field source 104 may be aligned inside of onecoil 114. The multiple internal magnetic field sources 104 may bedisposed within one common cavity 122, as shown in FIG. 2.Alternatively, the multiple internal magnetic field sources 104 may bedisposed within separate individually-sized cavities. By using multipleinternal magnetic field sources 104 within the same coil 114, the fluxchange experienced at the coil 114 may be increased. By increasing theamount of flux change, the amount of voltage induced in the coil 114 maybe increased.

A first instance of the internal magnetic field source 104 may apply afirst moving magnetic field to the coil 114. A second instance of theinternal magnetic field source 104 may apply a second moving magneticfield to the coil 114. The second internal magnetic source may bealigned relative to the coil 114 so that the polarity of the secondinternal magnetic field source experienced at the coil 114 substantiallymatches the polarity of the first internal magnetic field source. As themultiple internal magnetic field sources are rotated about theirrespective axes, each internal magnetic field source may showsubstantially the same polarity to the coil 114 at a given time. Whenthe south pole of the first internal magnetic field source is nearest tothe coil 114, the south pole of the second internal magnetic fieldsource may also be nearest to the coil 114. As the internal magneticfield sources continue to rotate, the north pole of the first internalmagnetic field source may be nearest to the coil 114 at the same timethe north pole of the second internal magnetic field source is nearestto the coil 114.

FIGS. 3-8 show the effect of the internal magnetic field source 104rotating near the coil 114. As the internal magnetic field source 104rotates polarity, an interaction between the stationary magnetic fieldand the moving magnetic field may pull magnetic flux associated with theinternal magnetic field source 104 back and forth across the coil 114.The coil 114 responds by opposing this change with a counterelectromagnetic field. The stationary magnetic field sources 116 and 118in FIGS. 3-8 are shown with an opposite polarity as compared to FIG. 1.In FIGS. 3-8, the north pole of the stationary magnetic field source 116is closer to the coil 114 than the south pole of the stationary magneticfield source 116, and the south pole of the stationary magnetic fieldsource 118 is closer to the coil 114 than the north pole of thestationary magnetic field source 118. Voltage plots 302, 402, 502, 602,702, and 802 show the voltage levels at the output nodes of the coil 114around the time frame that corresponds to the orientation of theinternal magnetic field source 104 shown in the respective figures. Theamplitude of the output voltages may be dependent on the strength of thestationary magnetic field sources 116 and 118 and the speed of rotationof the internal magnetic field source 104.

In FIG. 3, the north pole of the field source 104 is moving towards thecoil 114. As the north pole begins approaching the coil 114, magneticflux 304 from the internal magnetic field source 104 will be attractedtowards the stationary magnetic field source 118. Although some of themagnetic flux 304 may be experienced in the side portion of the coil 114that is nearer to the stationary magnetic source 116, more of themagnetic flux 304 will be experienced in the side portion of the coil114 that is nearer to the stationary magnetic source 118 when a northpole of the internal magnetic field source 104 is closer to the coil114. The stationary magnetic field between the stationary magnetic fieldsources 116 and 118 pulls the magnetic flux 304 from the internalmagnetic field source 104 across the portion of the coil 114 nearer tostationary magnetic field source 118. The magnetic flux 304 may bepulled in that direction because the magnetic flux 304 from the northpole of the internal magnetic field source 104 is attracted to the southpole of the stationary magnetic field source 118. Magnetic flux 308 mayalso pass between the stationary magnetic field source 116 and theinternal magnetic field source 104. The magnetic flux 308 may passthrough the core of frame that supports the coil 114.

The magnetic flux 304 that passes across the coil 114 induces a coilflux 306 through the coil 114. When the north pole of the internalmagnetic field source 104 is approaching, the coil flux 306 will travelfrom the portion of the coil 114 near the stationary magnetic source 118to the portion of the coil 114 near the stationary magnetic source 116.The interaction between the coil 114, the stationary magnetic field, andthe moving magnetic field induces a current and voltage in the coil 114.The voltage level at the output nodes of the coil 114 is illustrated inthe voltage plot 302. The induced voltage may increase from zero as theinternal magnetic field source 104 rotates until a peak voltage isachieved. As the internal magnetic field source 104 continues to rotate,the induced voltage begins to decease towards zero again.

In FIG. 4, the north pole of the field source 104 is moving away fromthe coil 114. As the north pole moves away from the coil 114, magneticflux 404 from the internal magnetic field source 104 will be attractedtowards the stationary magnetic field source 118. The stationarymagnetic field between the stationary magnetic field sources 116 and 118pulls the magnetic flux 404 from the internal magnetic field source 104across the portion of the coil 114 nearer to stationary magnetic fieldsource 118. The magnetic flux 404 may be pulled in that directionbecause the magnetic flux 404 from the north pole of the internalmagnetic field source 104 is attracted to the south pole of thestationary magnetic field source 118. Magnetic flux 408 may also passbetween the stationary magnetic field source 116 and the internalmagnetic field source 104. The magnetic flux 408 may pass through thecore of frame that supports the coil 114.

The magnetic flux 404 that passes across the coil 114 induces a coilflux 406 through the coil 114. When the north pole of the internalmagnetic field source 104 is moving away from the armature 106, the coilflux 406 will travel from the portion of the coil 114 near thestationary magnetic source 116 to the portion of the coil 114 near thestationary magnetic source 118. The coil flux 406 when the north pole ofthe internal magnetic field source 104 is moving away from the armature106 (e.g., FIG. 4) may be in the opposite direction as the coil flux 306when the north pole of the internal magnetic field source 104 isapproaching the armature 106 (e.g., FIG. 3). The interaction between thecoil 114, the stationary magnetic field, and the moving magnetic fieldinduces a current and voltage in the coil 114. The change in coil fluxdirection (compared to the direction in FIG. 3) results in a change ininduced current direction and thus an output voltage with the oppositepolarity. The voltage level at the output nodes of the coil 114 is shownin the voltage plot 402. The induced voltage may increase from zero(with an opposite polarity as compared to the voltage induced at FIG. 3)as the internal magnetic field source 104 rotates until a peak voltageis achieved. As the internal magnetic field source 104 continues torotate, the induced voltage begins to decease and approach zero.

In FIG. 5, the portion of the field source 104 that is closest to thecoil 114 is neither a north pole nor a south pole. FIG. 5 shows thenorth pole of the field source 104 moved away from the coil 114. It issubstantially equidistant from the coil as the south pole of the fieldsource 104. When neither pole of the field source 104 is facing the coil114, the voltage induced in the coil 114 may be near zero as shown involtage plot 502. As the field source 104 continues rotating and beginsto move the south pole of the field source 104 towards the coil 114, thevoltage output from the coil 114 may move away from zero.

In FIG. 6, the south pole of the field source 104 is shown movingtowards the coil 114. As the south pole approaches the coil 114,magnetic flux 604 may pass between the internal magnetic field source104 and the stationary magnetic field source 116. The magnetic flux 604may pass from the stationary magnetic source 116 to the internalmagnetic field source 104. Although some of the magnetic flux 604 may beexperienced in the side portion of the coil 114 that is nearer to thestationary magnetic source 118, more of the magnetic flux 604 may beexperienced in the side portion of the coil 114 that is nearer to thestationary magnetic source 116 when a south pole of the internalmagnetic field source 104 is nearer to the coil 114. The stationarymagnetic field between the stationary magnetic field sources 116 and 118may pull the magnetic flux 604 across the portion of the coil 114 nearerto the stationary magnetic field source 116. The magnetic flux 604 maybe pulled in that direction when the magnetic flux 604 from the northpole of the stationary magnetic field source 116 is attracted to thesouth pole of the internal magnetic field source 104. Magnetic flux 608may also pass between the internal magnetic field source 104 and thestationary magnetic field source 118. The magnetic flux 608 may passthrough the core of frame that supports the coil 114.

The magnetic flux 604 that passes across the coil 114 induces a coilflux 606 through the coil 114. When the south pole of the internalmagnetic field source 104 is approaching and the magnetic flux 604travels between the internal magnetic field source 104 and thestationary magnetic source 116, the coil flux 606 will travel from theportion of the coil 114 near the stationary magnetic source 118 to theportion of the coil 114 near the stationary magnetic source 116.

In FIGS. 3 and 6, the coil flux direction may be the same. When thenorth pole of the internal magnetic field source 104 is approaching thecoil 114 (FIG. 3), the coil flux direction may be the same as when thesouth pole of the internal magnetic field source 104 is approaching thecoil 114 (FIG. 6). The interaction between the coil 114, the stationarymagnetic field, and the moving magnetic field induces a current andvoltage in the coil 114. The voltage level at the output nodes of thecoil 114 is shown in the voltage plot 602. In plots 302 and 602, theoutput voltage may be about the same (in magnitude and polarity) wheneither the north pole or the south pole of the internal magnetic fieldsource 104 is approaching the armature 106. Alternatively, the outputvoltages of the two scenarios may be different based on other aspects ofthe generator 102, such as non-uniformities in magnetic source positionor strength. As shown in the plot 602, the induced voltage may increasefrom zero as the internal magnetic field source 104 rotates until a peakvoltage is achieved. As the internal magnetic field source 104 continuesto rotate, the induced voltage begins to decease towards zero again.

In FIG. 7, the south pole of the field source 104 is shown moving awayfrom the coil 114. As the south pole moves away from the coil 114,magnetic flux 704 may pass between the internal magnetic field source104 and the stationary magnetic field source 116. The magnetic flux 704may pass from the stationary magnetic source 116 to the internalmagnetic field source 104. The stationary magnetic field between thestationary magnetic field sources 116 and 118 pulls the magnetic flux704 across the portion of the coil 114 nearer to the stationary magneticfield source 116. The magnetic flux 704 may be pulled in that directionbecause the magnetic flux 704 from the north pole of the stationarymagnetic field source 116 is attracted to the south pole of the internalmagnetic field source 104. Magnetic flux 708 may also pass between theinternal magnetic field source 104 and the stationary magnetic fieldsource 118. The magnetic flux 708 may pass through the core of framethat supports the coil 114.

The magnetic flux 704 that passes across the coil 114 induces a coilflux 706 through the coil 114. When the south pole of the internalmagnetic field source 104 is moving away from the armature, the coilflux 706 will travel from the portion of the coil 114 near thestationary magnetic source 116 to the portion of the coil 114 near thestationary magnetic source 118. The coil flux when the south pole of theinternal magnetic field source 104 is moving away from the coil 114(e.g., FIG. 7) may be in the opposite direction as the coil flux 606when the south pole of the internal magnetic field source 104 wasapproaching the coil 114 (e.g., FIG. 6). The change in coil fluxdirection (compared to the direction in FIG. 6) results in a change ininduced current direction and thus an output voltage with the oppositepolarity.

In FIGS. 4 and 7, the coil flux direction may be the same. When thenorth pole of the internal magnetic field source 104 is moving away fromthe coil 114 (FIG. 4), the coil flux direction may be the same as whenthe south pole of the internal magnetic field source 104 is moving awayfrom the coil 114 (FIG. 7). The interaction between the coil 114, thestationary magnetic field, and the moving magnetic field induces acurrent and voltage in the coil 114. The voltage level at the outputnodes of the coil 114 is illustrated in the voltage plot 702. As shownin plots 402 and 702, the output voltage may be about the same (inmagnitude and polarity) when either the north pole or the south pole ofthe internal magnetic field source 104 is moving away from the coil 114.Alternatively, the output voltages of the two scenarios may be differentbased on other aspects of the generator 102, such as non-uniformities inmagnetic source position or strength. In plot 702, the induced voltagemay increase from zero (with an opposite polarity as compared to thevoltage induced at FIG. 6) as the internal magnetic field source 104rotates until a peak voltage is achieved. As the internal magnetic fieldsource 104 continues to rotate, the induced voltage begins to deceasetowards zero again.

In FIG. 8, the portion of the field source 104 that is closest to thecoil 114 is neither a north pole nor a south pole. FIG. 8 shows thesituation where the south pole of the field source 104 has moved awayfrom the coil 114 and is substantially equidistant from the coil as thenorth pole of the field source 104. When neither pole of the fieldsource 104 is facing the armature 106, the voltage induced in the coil114 may be near zero. As the field source 104 continues rotating andbegins to move the north pole of the field source 104 towards the coil114, then the voltage output from the coil 114 will again move away fromzero, as shown in FIG. 3.

FIGS. 3-8 illustrate a full rotation of the internal magnetic fieldsource 104. The internal magnetic field source 104 includes a north poleand a south pole. Other implementations use an internal magnetic fieldsource 104 with additional poles. Through the progression of FIGS. 3-8,the generator 102 may produce two flux changes at the coil 114 per poleof the internal magnetic field source 104 for each full rotation of theinternal magnetic field source 104. Because the internal magnetic fieldsource 104 of FIGS. 3-8 includes two poles, the generator 102 producesfour flux changes per full rotation of the internal magnetic fieldsource 104. A first flux change occurs in the time between FIGS. 3 and4. FIG. 3 shows the coil flux 306 moving from right to left, and FIG. 4shows the coil flux 406 moving from left to right. A second flux changeoccurs in the time between FIGS. 4 and 6. FIG. 4 shows the coil flux 406moving from left to right, and FIG. 6 shows the coil flux 606 movingfrom right to left. A third flux change occurs in the time between FIGS.6 and 7. FIG. 6 shows the coil flux 606 moving from right to left, andFIG. 7 shows the coil flux 706 moving from left to right. A fourth fluxchange occurs in the time between FIGS. 7 and 3. FIG. 7 shows the coilflux 706 moving from left to right, and FIG. 3 shows the coil flux 306moving from right to left.

The two flux changes per pole of the internal magnetic field source 104for each full rotation of the internal magnetic field source 104 resultsin an increase in frequency compared to a generator that produces onlyone flux change per pole of the internal magnetic field source 104 foreach full rotation of the internal magnetic field source 104. Thisincrease in frequency may increase the efficiency of the generator withhigher power densities. Using the flux interaction between the movingand stationary magnetic fields to increase the generator frequency mayresult in higher generator efficiency without requiring additional fieldsource poles or armature windings. Other implementations, however, mayuse additional field source poles and/or armature windings to produceeven higher generator efficiencies.

FIG. 9 shows an output waveform 902 of electrical energy induced in thearmature 106 of the generator 102 in response to a half rotation of theinternal magnetic field source 104. The output waveform 902 mayillustrate the voltage level that corresponds to the north pole of theinternal magnetic field source 104 approaching the coil 114 (as shown inFIG. 3) and then moving away from the coil 114 (as shown in FIG. 4).Alternatively, the output waveform 902 may illustrate the voltage levelthat corresponds to the south pole of the internal magnetic field source104 approaching the coil 114 (as shown in FIG. 6) and then moving awayfrom the coil 114 (as shown in FIG. 7). The output waveform 902 mayinclude peaks 904 and 906. In one implementation, the peak 904 maycorrespond to the north pole approaching the coil 114 and the peak 906may correspond to the north pole moving away from the coil 114. Inanother implementation, the peak 904 may correspond to the south poleapproaching the coil 114 and the peak 906 may correspond to the northsouth pole moving away from the coil 114. Alternatively, the peak 904may correspond to the south pole moving away from the coil 114 and thepeak 906 may correspond to the north pole approaching the coil 114. Inother implementations, the peak 904 may correspond to the north polemoving away from the coil 114 and the peak 906 may correspond to thesouth pole approaching the coil 114.

FIG. 10 shows an output waveform 1002 of electrical energy induced inthe armature 106 of the generator 102 in response to a full rotation ofthe internal magnetic field source 104. The output waveform 1002includes the peaks 904 and 906 shown in FIG. 9 corresponding to a halfrotation of the internal magnetic field source 104. The output waveform1002 also includes peaks 1004 and 1006 to complete a full rotation ofthe internal magnetic field source 104. The four peaks 904, 906, 1004,and 1006 of alternating polarity represent the four flux changes perfull rotation of an internal magnetic field source that has two poles.

If the peaks 904 and 906 correspond to the north pole of the internalmagnetic field source 104 approaching and then moving away from the coil114, then the peaks 1004 and 1006 may correspond to the south pole ofthe internal magnetic field source 104 approaching and then moving awayfrom the coil 114. Alternatively, if the peaks 904 and 906 correspond tothe south pole of the internal magnetic field source 104 approaching andthen moving away from the coil 114, then the peaks 1004 and 1006 maycorrespond to the north pole of the internal magnetic field source 104approaching and then moving away from the coil 114.

FIGS. 11 and 12 show generators with multiple armatures and multiplemagnetic field sources. In FIG. 11, the generator 1102 includes multipleinstances of the internal magnetic field source 104 aligned with therespective neutral points 126 of multiple instances of the armature 106.The multiple armatures 106 may be separated by an amount of space sothat their respective magnetic fields are isolated from each other.Alternatively, an isolation material (e.g., a ferrous or ferritematerial) may be placed between the armatures 106 to isolate onearmature from the other. The isolation material may be positioned sothat there is a gap between the isolation material and the adjacentarmatures. In one implementation, the stationary magnet of one armatureis positioned in attraction with the adjacent stationary magnet of theother armature, as shown in FIGS. 11 and 12. In other implementations,the stationary magnet of one armature may be positioned to be inrepulsion with the adjacent stationary magnet of the other armature.Positioning the stationary magnet of one armature to be in repulsionfrom the adjacent stationary magnet of the other armature may make iteasier to isolate the adjacent armatures through separation by aferrous/ferrite metal.

The multiple internal magnetic field sources 104 may be located ondifferent rotating shafts or they may both be located on a single shaft.As the multiple internal magnetic field sources 104 rotate, the movingmagnetic field interacts with the respective coils 114 and stationarymagnetic fields to generate electrical energy in each of the coils 114.

In FIG. 12, the phase of one of the internal magnetic sources 104 of thegenerator 1202 is about 90° out of phase with the other of the internalmagnetic sources 104. In one implementation, as shown in FIG. 12, thesouth pole of the left internal magnetic field source 104 may be facinga coil 114 when neither pole of the right internal magnetic field source104 is directly facing a coil 114. When the internal magnetic fieldsources 104 turn about 90° together, the south pole of the rightinternal magnetic field source 104 may face a coil 114 when neither poleof the left internal magnetic field source 104 is directly facing a coil114. This arrangement generates two current phases.

By staggering one of the internal magnetic sources 104 about 90° out ofphase with the other of the internal magnetic sources 104, the amount ofmagnetic drag experienced as the internal magnetic sources 104 rotatemay be reduced. As one of the internal magnetic field sources 104 isrotating away from a portion of the armature 106 (e.g., the core of theframe), another of the internal magnetic field sources 104 may berotating towards the core of the armature 106. When an internal magneticfield source 104 is rotating away from the core of the armature 106,there may be an attraction force between the internal magnetic fieldsource 104 and the core. That attraction force may make it moredifficult to turn the shaft that supports the internal magnetic fieldsource 104. When an internal magnetic field source 104 is rotatingtoward the core of the armature 106, there may also be an attractionforce between the internal magnetic field source 104 and the core. Theattraction force between the internal magnetic field source 104 movingtowards the core of its associated armature 106 may counteract at leastsome of the attraction force between the internal magnetic field source104 moving away from the core of its associated armature 106. Therefore,the multiple phase system of the generator 1202 may reduce the amount ofmechanical energy required to turn the shaft.

FIGS. 13-15 show other configurations for the stationary magnetic fieldsources of a generator. In FIG. 13, the generator 1302 includesstationary magnetic field sources 116 and 118 disposed on the ends of abent core 120 (e.g., horseshoe shaped).

FIG. 14 shows a generator 1402 with a coil 114 wrapped about a core 120that may carry multiple stationary magnetic fields along the axis of thecoil 114. A first stationary magnetic field may pass between thestationary magnetic field sources 1404 and 1406 through the core 120. Asecond stationary magnetic field may pass between the stationarymagnetic field sources 1408 and 1410 through the core 120. Additionalstationary magnetic sources may also be positioned to pass additionalstationary magnetic fields through the core 120.

FIG. 15 shows an end view of a generator 1502 that includes four or morestationary magnetic fields passing through a core 120 of an armature. Afirst magnetic field passes through the core 120 between the stationarymagnetic field source 1504 and another stationary magnetic field sourcethat is not visible in this perspective. A second magnetic field passesthrough the core 120 between the stationary magnetic field source 1506and another stationary magnetic field source that is not visible in thisperspective. A third magnetic field passes through the core 120 betweenthe stationary magnetic field source 1508 and another stationarymagnetic field source that is not visible in this perspective. A fourthmagnetic field passes through the core 120 between the stationarymagnetic field source 1510 and another stationary magnetic field sourcethat is not visible in this perspective. The other stationary magneticsources that are not visible in this perspective may be disposed on theother end of a bent core 120 (e.g., a horseshoe shaped core). Theseother magnetic field sources may be directly below the stationarymagnetic field sources 1504, 1506, 1508, and 1510 in the perspective ofFIG. 15. Furthermore, additional stationary magnetic sources (e.g., morethan the four shown) may also be positioned to pass additionalstationary magnetic fields through the core 120.

The term “coupled” may encompass both direct and indirect coupling.Thus, first and second parts are said to be coupled together when theydirectly contact one another, as well as when the first part couples toan intermediate part which couples either directly or via one or moreadditional intermediate parts to the second part. The term “position,”“location,” or “point” may encompass a range of positions, locations, orpoints.

While various embodiments of the invention have been described, it willbe apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible within the scope of theinvention. Accordingly, the invention is not to be restricted except inlight of the attached claims and their equivalents.

1. A generator, comprising: a frame that defines a cavity and an outersurface; a coil disposed about the outer surface of the frame; aninternal magnetic field source disposed within the cavity of the frameand configured to apply a moving magnetic field to the coil; and astationary magnetic field source configured to apply a stationarymagnetic field to the coil, wherein the stationary magnetic fieldinteracts with the moving magnetic field to generate an electricalenergy in the coil.
 2. The generator of claim 1, wherein the internalmagnetic field source is located adjacent to a substantially neutralpoint of the coil where flux change from the internal magnetic fieldsource would produce a minimal amount of induced electromagnetic forcein the coil before addition of the stationary magnetic field.
 3. Thegenerator of claim 2, wherein the internal magnetic field sourcegenerates the moving magnetic field when rotated about an axis in aposition adjacent to the substantially neutral point of the coil, andwherein a north pole of the internal magnetic field source and a southpole of the internal magnetic field source alternate being nearer to thecoil as the internal magnetic field source rotates about the axis. 4.The generator of claim 1, wherein the frame comprises a core made of amagnetizing material, wherein the coil is wound on the frame about thecore, and wherein the stationary magnetic field source is coupled withthe core to apply the stationary magnetic field along or through thecore.
 5. The generator of claim 4, further comprising a secondstationary magnetic field source, wherein the stationary magnetic fieldsource is coupled with a first end portion of the core, wherein thesecond stationary magnetic field source is coupled with a second endportion of the core, wherein the stationary magnetic field source andthe second stationary magnetic field source are positioned in attractionto each other.
 6. The generator of claim 4, wherein a portion of theframe that supports the coil is made of a non-conducting andnon-magnetizing material.
 7. The generator of claim 1, wherein thecavity of the frame is at least partially filled with a magnetizingmaterial that at least partially surrounds the internal magnetic fieldsource.
 8. The generator of claim 1, wherein the coil comprises aconductive material wound about the core in a substantially uniformwinding pattern, and wherein the internal magnetic field source isadjacent to a longitudinal center point of the coil.
 9. The generator ofclaim 1, wherein an interaction between the coil, the stationarymagnetic field, and the moving magnetic field produces two flux changesat the coil per pole of the internal magnetic field source for each fullrotation of the internal magnetic field source.
 10. The generator ofclaim 1, wherein the stationary magnetic field source serves to pullmagnetic flux associated with the internal magnetic field source backand forth across the coil as a polarity of the internal magnetic fieldsource experienced at the coil alternates between north and south. 11.The generator of claim 10, wherein more of the magnetic flux associatedwith the internal magnetic field source is experienced in a first sideportion of the coil than in a second side portion of the coil when anorth pole of the internal magnetic field source is nearer to the coil,and wherein more of the magnetic flux associated with the internalmagnetic field source is experienced in the second side portion of thecoil than in the first side portion of the coil when a south pole of theinternal magnetic field source is nearer to the coil.
 12. The generatorof claim 1, further comprising a second internal magnetic field sourcedisposed within a cavity of the frame and configured to apply a secondmoving magnetic field to the coil.
 13. The generator of claim 12,wherein the second internal magnetic field source is aligned relative tothe coil so that a polarity of the second internal magnetic field sourceexperienced at the coil substantially matches a polarity of the internalmagnetic field source as the internal magnetic field sources are rotatedabout their respective axes.
 14. The generator of claim 1, wherein theframe, the coil, and the stationary magnetic field source make up afirst armature of the generator, the generator further comprising: asecond armature including a coil and a second stationary magnetic fieldsource, wherein the second stationary magnetic field source applies asecond stationary magnetic field to the coil of the second armature; anda second internal magnetic field source disposed within a cavity of thecoil and configured to apply a second moving magnetic field to the coilof the second armature, wherein the second stationary magnetic fieldinteracts with the second moving magnetic field to generate anelectrical energy in the coil of the second armature.
 15. The generatorof claim 14, wherein the internal magnetic field source and the secondinternal magnetic field source are coupled with a rotating shaft, andwherein a polarity of the internal magnetic field source is about ninetydegrees out of phase with a polarity of the second internal magneticfield source.
 16. A generator, comprising: a core; a coil disposed aboutthe core; a first stationary magnetic field source disposed on a firstend portion of the core; a second stationary magnetic field sourcedisposed on a second end portion of core, wherein the first and secondstationary magnetic field sources are configured to apply a stationarymagnetic field to the coil; and an internal magnetic field sourcedisposed within a cavity of the coil and configured to apply a movingmagnetic field to the coil.
 17. The generator of claim 16, wherein thecoil comprises an armature winding that conducts electrical energygenerated in response to an interaction between the coil, the movingmagnetic field, and the stationary magnetic field.
 18. The generator ofclaim 16, wherein the internal magnetic field source is located adjacentto a substantially neutral point of the coil where flux change from theinternal magnetic field source would produce a minimal amount of inducedelectromagnetic force in the coil before addition of the stationarymagnetic field; wherein the internal magnetic field source generates themoving magnetic field when rotated about an axis in a position adjacentto the substantially neutral point of the coil; and wherein a north poleof the internal magnetic field source and a south pole of the internalmagnetic field source alternate being nearer to the coil as the internalmagnetic field source rotates about the axis.
 19. The generator of claim16, wherein the first and second stationary magnetic field sources applythe stationary magnetic field along or through the core; and wherein thefirst and second stationary magnetic field sources serve to pullmagnetic flux associated with the internal magnetic field source backand forth across the coil as a polarity of the internal magnetic fieldsource experienced at the coil alternates between north and south.
 20. Agenerator, comprising: a coil of conductive material; a stationarymagnetic field source configured to apply a stationary magnetic fieldsubstantially along a longitudinal axis of the coil; and an internalmagnetic field source disposed within a cavity of the coil andconfigured to apply a moving magnetic field to the coil, wherein thestationary magnetic field source causes magnetic flux associated withthe internal magnetic field source to be alternatively attracted towardsa first side portion of the coil or a second side portion of the coilbased on a polarity of the internal magnetic field source.
 21. Thegenerator of claim 20, wherein the internal magnetic field source islocated adjacent to a substantially neutral point of the coil where fluxchange from the internal magnetic field source would produce a minimalamount of induced electromagnetic force in the coil before addition ofthe stationary magnetic field; wherein the internal magnetic fieldsource generates the moving magnetic field when rotated about an axis ina position adjacent to the substantially neutral point of the coil; andwherein a north pole of the internal magnetic field source and a southpole of the internal magnetic field source alternate being nearer to thecoil as the internal magnetic field source rotates about the axis.
 22. Amethod of generating electrical energy, comprising: positioning aninternal magnetic field source within a cavity of a coil of conductivematerial at a location where the internal magnetic field source isadjacent to a substantially neutral point of the coil; applying astationary magnetic field along a longitudinal axis of the coil; andalternating a polarity of the internal magnetic field source, whereinthe stationary magnetic field causes magnetic flux associated with theinternal magnetic field source to be alternatively attracted towards afirst side portion of the coil or a second side portion of the coilbased on a polarity of the internal magnetic field source.
 23. Themethod of claim 22, wherein the internal magnetic field source comprisesa magnet with multiple poles, and wherein the step of alternating thepolarity comprises rotating a shaft coupled with the internal magneticfield source.
 24. The method of claim 22, wherein the coil is disposedabout a core, wherein the step of applying the stationary magnetic fieldcomprises: positioning a first stationary magnetic field source on afirst end portion of the core; and positioning a second stationarymagnetic field source on a second end portion of the core so that thesecond stationary magnetic field source is in attraction with the firststationary magnetic field source.
 25. The method of claim 22, whereinthe step of positioning the internal magnetic field source comprisesidentifying the substantially neutral point of the coil where fluxchange from the internal magnetic field source would produce a minimalamount of induced electromagnetic force in the coil before thestationary magnetic field is applied to the coil.